Magnetron sputter source

ABSTRACT

To optimize the yield of sputtered-off material as well as the service life of the target on a magnetron source, in which simultaneously good attainable distribution values of the layer on the substrate, stable over the entire target service life, a concave sputter face  20  in a configuration with small target-substrate distance d is combined with a magnet system to form the magnetron electron trap in which the outer pole  3  of the magnetron electron trap is disposed stationarily and an eccentrically disposed inner pole  4  with a second outer pole part  11  is developed rotatable about the central source axis  6.

[0001] The invention relates to a magnetron sputter source according tothe preamble of patent claim 1 and its use according to patent claim 17.

[0002] Magnetron sputter sources of this type have been known for manyyears and serve for coating substrates in a vacuum. Such magnetronsputter sources are distinguished thereby that with the aid of amagnetic field a dense plasma is generated in front of the targetsurface to be sputtered, which permits sputtering the target through ionbombardment at high rates and attaining a layer on the substrate withhigh growth rate. In such magnetron sputter sources the magnetic fieldserves as an electron trap which determines significantly the dischargeconditions of the gas discharge and plasma confinement. The magneticfield of such a magnetron electron trap is developed such that in theregion of the back side of a target to be sputtered closed magnetic poleloops are disposed which do not intersect and, in special cases, form anannular configuration and can also be disposed concentrically, withthese magnetic pole loops being disposed antipolar-wise and spaced apartsuch that field lines close between the poles and herein at leastpartially penetrate the target where they determine the electron trapeffect in the region of the sputter faces. Due to the pole loopsdisposed one within the other or concentrically, in the target surfaceregion a magnetic field is developed in the form of a tunnel, whichforms a closed loop in which the electrons are captured and guided.Based on this characteristic structuring of the magnetron electron trap,an annular plasma discharge is also generated with inhomogeneous plasmadensity distribution which results in the target likewise being erodednonuniformly through the nonuniform ion bombardment. In such a magnetrondischarge typically an annular erosion trench is generated duringoperation whereby also problems in the layer thickness distribution onthe substrate result and have to be solved. A further disadvantage isthat through the developing trench-form erosion pattern of the targetthe utilization of the target material becomes reduced.

[0003] These problems have already been recognized according to DE OS 2707 144 corresponding to U.S. Pat. No. 5,284,564. The solution proposedis to generate between the loop-form plasma discharge and the target arelative movement such that the plasma sweeps over the target surface.Thereby the erosion profile on the target is to be broadened orflattened and simultaneously the layer distribution on the substratedisposed in front of it to be improved. In the case of rectangularmagnetron sputter configurations the magnet system which generates theelectron trap is moved, for example according to FIG. 1, back and forthbehind the flat target. In the case of round sputter sources, the magnetsystems according to FIGS. 22 to 25 is, for example, rotated behind thetarget about the target axis. Thereby is attained that the plasma loopsweeps over the round target plate. FIGS. 22 and 25 show in additionthat the electron trap loop can be shaped differently and can therebyaffect the resulting erosion profile.

[0004] In configurations in which the substrates are disposedstationarily opposite the magnetron target or rotate about theirinternal axes in a plane in front of the target, or in which already inthe substrate plane over a maximally large area high homogeneityrequirements of the coating must be met, special problems areencountered since the distribution and the material utilizationproblematic must primarily be solved already at the source side andcannot be solved by moving the substrate past such source. Coatinginstallations of this type, in which disk-form substrates aretransferred in cycles and positioned in front of a magnetron sputtersource and coated there, have greatly gained in significance. In thisway today preferably semiconductor wafers are worked or coated for theproduction of electronic structural components, as well as storage disksfor the production of magnetic storage plates and for the production ofoptical and optomagnetic storage plates.

[0005] For coating stationarily disposed disk-form substrates firstannular sputter sources were already used before 1980. As stated,through the annular plasma loop a pronounced annular erosion trench isdeveloped in the target, which leads to problems with the layerdistribution on the substrate at high precision requirements. Thereforein the case of such source configurations the distance between targetand the substrate to be coated must be relatively large, typically mustbe in the range from 60 to 100 mm. In order to attain good distributionvalues, in addition the target diameter must be selected to be somewhatgreater than the substrate diameter. The relatively large targetsubstrate distance as well as also the relatively large oversizing ofthe target diameter practically led to the fact that the utilization ofthe material sputtered off was overall poor. Due to the low economyfollowing as a consequence and the ever increasing distributionrequirements made of the coating, round magnetron source configurationswith rotating magnet systems were developed, which make possible furtherimprovements in this respect. In order to increase the materialutilization and the coating rate it was found that the target substratedistance and the target diameter had to be decreased. But this is onlypossible if, for one, the plasma confinement takes place such that theplasma extension does not disturb the substrate to be coated and, foranother, the target removal is homogeneous over the surface and inparticular also in the proximity of the target center is sputtered off.

[0006] A first improvement step could be achieved according to aconfiguration such as is depicted in FIG. 1a. The magnet system 2 iscomprised of an outer annular magnet pole 3 and an inner eccentricallyoffset counter pole 4. The magnet system 2 is supported rotatably abouta central rotation axis 6 and is rotated in the rotational direction 7by a drive, such as with an electromotor, with respect to the stationarytarget. Due to the eccentric configuration of the inner pole 4, uponapplication of a discharge voltage on the target 1 an eccentricallyrotating plasma loop is generated, which sweeps over a major portion ofthe target. In FIG. 1b this configuration is shown in cross section,wherein the magnet system 2 is rotatably supported about the sourcecenter axis 6 in the rotational direction 7, a substrate s is disposedat a distance d (typically in the range from 40 to 60 mm) from the roundtarget plate 1, with the target 1 being, for example, water-cooled via acooling device 8. The magnet system 2 is formed of permanent magnets 3,4 and these are disposed such that the outer pole 3 and the inner pole 4are spaced apart and antipolar such that the generated field lines Bpenetrate through the target 1 and form across the target surface theclosed tunnel-form magnetic field loop, which forms an electron trap.The return of the permanent magnets takes place across a yoke plate 5 ofhighly permeable material, such as iron, which is disposed on that sideof the permanent magnet poles which is further removed from target 1. Togenerate an eccentricity of the plasma loop, the inner pole 4 was offsetwith respect to the rotation axis 6. By choosing this eccentricity theerosion and distribution characteristic can be optimized in a certainrange.

[0007] A further significant improvement of the magnet systemconfiguration is possible through the completely eccentric formation ofthe magnetic circuit according to FIGS. 1c and 1 d. The width, depictedin FIG. 1c and substantially uniform, of the magnetic tunnel along theentire closed loop permits a more constant and efficient electron trapeffect and especially a clearer definition of the eccentricity of theplasma loop, which leads to better results. In FIG. 1d a furtherembodiment is shown, in which the plasma loop is folded into itselfagain for example in the form of a type of cardioid curve. Depending onthe magnitude of the target and substrate dimensions, a large number ofpossible loop forms result, such as for example also folded plasmaloops, which serve for optimization of the sputter and distributionconditions on the substrate. The advantage of these rotatingconfigurations lies not least therein that the results can be wellcalculated in advance via the geometric formation alone. Furthersimulation calculations are possible for the optimization of the design.

[0008] Magnetron sputter sources with round planar target and withrotating magnet systems have been marketed for many years by BalzersAktiengesellschaft in Liechtenstein, for example under the typedesignation AR 125, and are also described in the operating instructions(BB 800 463 BD) for the source in the first edition May 1985.

[0009] A further option for affecting the erosion profile comprisesshifting the outer magnet pole in the direction of the target sputterface, parallel to the source axis 6, as is shown in FIG. 2. Thereby thefield line course B is changed, in particular flattened, such that theerosion profile can be broadened. In such configurations with magnetpoles elevated it is also possible to elevate the inner pole 4 in thecenter if necessary also over the sputter face of the target 1 if thetarget in the center has an opening provided for this purpose and theprovided sputter characteristic permits such. In a stationary coatingconfiguration of substrate s this source formation has the disadvantagethat, on the one hand, relatively large target to substrate distancesare necessary, the utilization of the sputtered material which arriveson the substrate s is relatively low, since the zones in the outerregion, which cannot be utilized, are proportionally large and thetarget utilization is lower than in rotating systems.

[0010] A further and significantly improved formation of a magnetronsputter source configuration for coating disk-form substrates s isdepicted in FIG. 3 and described in EP 0 676 791 B1 corresponding toU.S. Pat. No. 5,688,381. This source configuration also has elevatedouter poles 3, wherein the pole region itself is preferably developed asa permanent magnet and the magnetic return with respect to the centralinner pole 4 takes place across an iron yoke 5. In this source thetarget body 1 is developed such that it is arched inwardly, thus isconcave, and the electron trap is defined such that the hollow volumegenerated by the inward arching of target 1 forms substantially theplasma discharge volume. It becomes hereby possible to move with thesubstrate s very close to the target 1, for example 35 mm at a substratediameter of 120 mm, with the target diameter not being substantiallylarger than the substrate diameter. Hereby the discharge volume betweenthe concavely developed target 1 and the substrate is substantiallydelimited by the substrate and the sputter face. This results in thesputtered material being transferred to a very large extent onto thesubstrate and the margin losses being low. With this sourceconfiguration therefore high coating rates at very good economy arepossible. Certain restrictions however occur thereby that the control ofthe erosion profile and of the distribution and the attainment ofreproducible conditions, in particular over the target service life, isdifficult in this respect. Attempts have therefore been made to affectwith additional outer pole configurations 3 a, which are disposedbetween the inner pole 4 and the outer pole 3, the plasma discharge suchthat at deepened erosion profile a shift of the plasma ring takes placein order to attain a specific compensation effect. At very high requireddistribution requirements and material utilization degrees this methodhas, however, certain restrictions.

[0011] The present invention therefore has as its object to eliminatethe disadvantages of prior art. In particular, the present invention hasas its object to realize a magnetron sputter source with elevated outerpole magnet configuration, which combines the advantages of high sputterrates at high degrees of material utilization with very good achievabledistribution values on the substrate during the entire target servicelife, at stable and reproducible conditions. In addition, the magnetronsputter source has high overall economy.

[0012] Building on a magnetron sputter source of the above cited typethis object is attained through its formation according to thecharacterizing clause of claim 1.

[0013] Thereby that according to the invention the annular outer poledoes not lie in the same plane as the inner pole and, in the marginregion of the round target body, is elevated with respect to the innerpole and the rotatable magnet system part receives an inner poledisposed eccentrically to the source axis and receives a second outerpole part between inner pole and static outer pole such that withrotation the tunnel loop of the magnetic field eccentrically sweeps overthe sputter face, at high rate and material utilization a good andstable distribution results over the entire target service life whichleads to a significant increase of economy. Preferred applications areobtained according to claim 17. Preferred further embodiments of theinventive magnetron sputter source are defined in claims 2 to 16.

[0014] FIGS. 1 to 3 reproduce schematically prior art and FIGS. 4 to 8reproduce by example and schematically the configuration according tothe invention. In the Figures depict:

[0015]FIG. 1a in top view a rotatable round magnet system configurationwith outer pole and with inner pole disposed eccentrically to thecentral axis according to prior art,

[0016]FIG. 1b in cross section and schematically the magnet systemconfiguration according to FIG. 1a with target and substrateconfiguration according to prior art,

[0017]FIG. 1c in top view a further rotatable magnet systemconfiguration with the magnet system disposed eccentrically to therotation axis according to prior art,

[0018]FIG. 1d a further implementation of a rotatable eccentricallydisposed magnet system with magnet configuration similar to a cardioid,

[0019]FIG. 2 in cross section and schematically a magnetronconfiguration with an outer pole elevated with respect to the inner polefor stationarily disposed substrate planes according to prior art,

[0020]FIG. 3 in cross section and schematically a further configurationwith an outer pole elevated with respect to the inner pole and concavelydeveloped target according to prior art,

[0021]FIG. 4 schematically and in top view a magnet system configurationaccording to the invention with stationary outer pole and rotatableeccentrically disposed inner pole and outer pole part, with thestationary outer pole 3 being elevated with respect to the inner pole onthe target margin,

[0022]FIG. 5 a cross section of a configuration according to theinvention according to FIG. 4,

[0023]FIG. 6 a further example according to the invention shown indetail and schematically in section,

[0024]FIG. 7 an example of a measured curve of the average distributionon a substrate over the target service life,

[0025]FIG. 8 the cross section profile of one half of a target as anexample of the erosion which can be attained according to the inventionover the target service life.

[0026] In FIG. 5 is depicted a magnetron sputter source in cross sectionand schematically. The sputter target 1 is developed as an annulartarget body, which has substantially a concavely developed sputter face20. The sputter face 20 can per se also be developed such that it isplanar, but the concave development is significantly more advantageoussince with small substrate distance d the discharge volume comprisesessentially the sputter face 20 and the substrate face s and thus theloss zone in the margin region is minimal. The round target 1 forcoating storage plates s is advantageously developed such that it isannular which permits guiding an electrode 16 through in the centeralong the source center axis, which serves simultaneously as center maskfor the disk-form substrate s. The substrate s is disposed at a smalldistance d from target 1 and the diameter of target 1 is only slightlygreater than the diameter of substrate s. The discharge volume formedthereby is delimited by an electrode 15 encompassing this volume. Due tothis formation, the residual surfaces 15 and 16, which are also coated,are minimized relative to the usable surface of the substrate s and theso-called material transfer factor is thereby increased. The electrodes15 and 16 are conventionally with DC current operation switchedanodically and the target 1 cathodically. But, in known manner, suchelectrodes can also be operated floating or at a bias. The magnet systemcomprises an encompassing outer pole 3 elevated in the margin region oftarget 1 and an inner pole 4, eccentrically disposed to the source axis6 behind target 1, wherein between the inner pole 4 and the outer pole 3a second outer pole part 11 is disposed, which assumes a partialfunction of the outer pole 3. The second outer pole part 11 is, forexample, developed as a segment-like part which represents a type ofcutout from the annular outer pole 3 but is disposed offset androtatable. The poles directed toward target 1 are defined such that theinner pole 4 represents a counter pole to the outer pole 3 and to theouter pole part 11 such that the already described tunnel-form magneticfields B are generated across the sputter face 20, which forms anannular closed loop for the plasma confinement. The poles 3, 4 and 11are developed with advantage directly from permanent magnet material,wherein preferably permanent magnet material of the types rare earths isemployed such as cobalt, samarium and in particular of the typeneodymium. For the magnetic return in the back side region of thepermanent magnets in known manner iron yokes 5, 10 are employed. Theoutput pole 3 is according to the invention disposed stationarily alongthe target periphery encompassing the latter and parallel to the centralaxis 6 elevated with respect to the inner pole 4 and the second outerpole part 11 on the target margin. By the degree of elevation of theouter pole 3 with respect to the inner pole 4 within certain limits theerosion profile 21, which is generated through the sputter process ontarget 1, can be affected and optimized. But the outer pole 3 shouldadvantageously not be shifted beyond the target margin in the axialdirection 6. The eccentrically disposed inner pole 4 and the outer polepart 11, also disposed eccentrically, are mounted on a second returnyoke 10 rotatable about axis 6 and supported such that between the firstreturn yoke 5, which encompasses the second return joke 10, a small airgap is formed such that the inner pole magnets 4 and the magnets 11 ofthe outer pole part 11 with the second yoke 10 can rotate freely aboutaxis 6. The second yoke 10 is advantageously developed as a round plate,which can receive the magnets 4, 11 in a magnet casing 12. In spite ofstationary magnet system part 3, 5, through the rotation of the magnetsystem part 4, 10, 11 is achieved that the tunnel-form magnet field loopB, and thus the generated plasma ring discharge, can be movedeccentrically with respect to axis 6 and thereby the plasma sweeps overthe sputter face 20 in the desired manner. The generated erosion profile21 can hereby be predetermined and affected in the desired manner.

[0027] The source according to the invention corresponding to FIG. 5 isdepicted in top view to illustrate the exemplary magnet configuration inFIG. 4. On the return yoke 10, which, as a rule, comprises iron areeccentrically mounted magnets 4 which represent the inner pole, with theinner pole 4 being disposed eccentrically such that it extends withadvantage just into the proximity of the center axis 6. The second outerpole part 11, which is developed in the form of segments, also comprisespermanent magnets and is disposed on the round plate-form yoke spacedapart with respect to the inner pole 4 such that the magnetic fieldlines close across poles 11 and 4 and in the region, in which no secondouter pole part 11 is adjacent with respect to the inner pole 4, thefield lines close across the inner pole 4 and the outer pole 3. Themagnet system part mounted on the rotatable yoke plate 10 rotates inrotational direction 7 about the central source axis, with the outerpole 3 remaining stationary. The thereby developed eccentricallydisposed magnetron electron trap thus rotates about axis 6 and thus alsodoes the plasma loop.

[0028] The target-substrate distance to the lowest site of the concavetarget 1 is advantageously smaller than 60 mm and values of less than 40mm yield very good conditions with respect to material utilization anddistribution and values of less than 35 mm mean still better transferfactors at typical substrate disk diameters of 120 mm. In order to beable to ensure a stable plasma discharge, distances below 20 mm can nolonger be recommended. The target diameter should herein be up to 30%greater than the substrate diameter but preferably not greater than by25%. The source is advantageously suitable for disk-form substrates, inparticular with a diameter of 50 to 150 mm, wherein for those in therange of 70 to 150 mm the configuration is especially suitable and inwhich lie the typical dimensions for storage plates.

[0029] A practical and preferred embodiment example of the sourceaccording to the invention is depicted in detail and schematically incross section in FIG. 6. The sputter target 1 is preferably developed asan annular body with an opening in the center. The annular body isadvantageously concave in the region of the sputter face 20, developedchannel-form and especially advantageously has substantially the form ofa V. The outer margin of target 1 is disposed somewhat higher than theinner margin. The lowest point of the channels, or of the V-form sputterface 20, is disposed with respect to the sputter axis 6 approximately atone half the target radius Rt. The target is cooled in the conventionalmanner with cooling means on the back side, for example with a coolingplate 27 through which flows cooling water. On the sputter-face sideperiphery of target 1 is disposed an annular diaphragm 15, which isswitched as counter electrode to target 1. In the present example theanode 15 is electrically connected to installation potential or toground potential. The anode 15 comprises a receiving opening 28, intowhich the disk-form substrate s is placed. The configuration isdeveloped such that with respect to the lowest point of the sputter face20 and the substrate a distance d of 20 to 60 mm is generated,preferably in the range from 20 to 40 mm. This configuration overallforms the plasma volume, and it must be ensured that the area ofelectrode 15 not utilizable for the coating remains small. The opening28 herein has for example a diameter of approximately 120 mm in order tobe able to receive corresponding substrates s. To attain even betterdistribution values, substrates s can in the region of opening 28additionally be also rotated about their axis 6 or even be disposedrotatable and slightly offset eccentrically with respect to axis 6. Itis also possible to position more than one substrate in plane 28.Further, by inclining the substrate plane with respect to the verticalplane through the source axis 6, a further setting parameter can beintroduced, if especially difficult distribution requirements make suchnecessary. For optical storage plates which have an opening in thecenter, a central mask 16 is required, which simultaneously acts asmounting and as additional anode. The center mask 16 is guided throughan opening of target 1 in the center and is advantageously cooled via acooling means inlet 26. In addition, via this center mask 16 thedischarge gas 25 can be supplied. The center mask is guided in itsextension through the cooling plate 27 and the rotatable magnet systempart 4, 10, 11, 12 along axis 6. The center mask 16 can also be operatedsuch that it is electrically floating and in this case only theelectrode 15, which encompasses the substrate S, is switched anodically.

[0030] The inner pole 4 disposed eccentrically with respect to therotation axis 6 and the second outer pole part comprise rare earthmagnets and are mounted on the second iron yoke 10, which is developedas a round carrier plate, wherein the entire magnet system part isclosed with a casing cover 12. This rotatable magnet system part isdriven via a driving arrangement 30, for example an electromotor withgearing. The outer and stationarily disposed yoke 5, which ismagnetically coupled with the rotatable yoke 10 is elevated along theperiphery of target 1 and in the end region carries outer pole magnets3, which form the poles such that over the sputter face 20 a tunnel-formmagnetic field B with a closed loop is generated. Through the rotationof the magnet system part 4, 10,11 the magnetic field loop is moved overthe sputter face 20 eccentrically about the central axis 6, whereby thedesired erosion characteristic is generated. The outer pole 3advantageously does not extend beyond the periphery of target 1 in thedirection of the substrate plane s. Additional measures for protectingthe magnets 3 and to prevent parasitic discharges in undesirable regionsin the pole proximity are possible thereby that labyrinth-like anddark-space umbrella-like coverings between target periphery and outerpole 3 are provided. This can, as shown in the depicted example, becombined with corresponding formation of the outer anode 15. The entiresource can in conventional manner be installed into a vacuum-tightcasing 17, which via a vacuum seal 18 is flanged to a vacuuminstallation 31. A realized magnetron sputter source depicted by examplehas the following dimensions:

[0031] target diameter: 150 mm

[0032] target thickness: 30 mm

[0033] target form: essentially V-form according to FIG. 8 where Thdenotes the target thickness and Rt defines the target radius in mm anda the sputter original face 20

[0034] target material: silver, or silver alloy

[0035] target utilization: >45%

[0036] transfer factor of the target material: >45%

[0037] layer thickness distribution: approximately 5%

[0038] target substrate distance: d=30 mm

[0039] sputter gas and pressure: Ar, approximately 10⁻³ millibar

[0040] number of CDR coatings: >110,000/target

[0041] substrate diameter: 120 mm (CDR)

[0042] layer thickness on substrate: approximately 700 Å.

[0043] It was found that with the present invention primarily over theentire target service life with more than 110,000 coated storage platesa layer thickness precision over the useful area of the storage plate ofapproximately 5% could be maintained. This result is shown in FIG. 7.The distribution U in percent over the target service life, relative tothe number T1 of coated substrates s given in units of thousands, has ahighly uniform and constant course in the range of approximately 3.5 to5% distribution accuracy. A further advantage of the configurationcomprises that the target material is better utilized, wherewith, on theone hand, a relatively large number of coatings T1 is possible beforethe target 1 must be replaced and, on the other hand, material can besaved, which leads overall to greater economy. A highly significantaspect herein is moreover that over the service life TL of target 1 notonly the distribution proportions U remain constant but also thedischarge conditions. This is primarily attained through the uniform andspecific erosion characteristic of the source over the target servicelife, as is shown in FIG. 8 in conjunction with an example.

[0044] In FIG. 8 is depicted a cross section through one half of anannular target with V-form sputter original face 20 with profile curve aand with two erosion profile curves b and c after different operatingtimes. Profile b shows a formation after approximately ⅔ of the targetservice life and profile c approximately at the end of the targetservice life. It is immediately evident that the profiles are highlyuniform and hardly differ in form and extend essentially symmetrically.This also causes the plasma conditions to remain constant andreproducible, even over relatively steep erosion paths Th of target 1.

[0045] For storage plate applications of said type with diameters in therange from 50 to 150 mm an annular target developed concavely issuitable, which means disposed annularly about axis 6 has preferably atype of V-form profile. Herein the inclination of the inner face withrespect to a planar face is to be selected of advantage in the rangefrom 5 to 30 degrees, preferably in the range from 10 to 20 degrees,with the inclination of the outer face to be selected in the range from12 to 30 degrees, preferably in the range from 15 to 25 degrees in orderto attain good results. The lowest point of the concave target liesherein approximately in the central radius region of target 1,preferably in the range of the 0.4- to the 0.7-fold of the targetradius.

[0046] The sputter source according to the invention is per se suitableto sputter all known materials. The source is preferably applicable forsputtering metals or metal alloys. Reactive processes in which, inaddition to argon, also an additional reactive gas, such as for exampleoxygen or nitrogen, are employed, are also possible, Apart from a pureDC sputtering process, also high frequency, medium frequency or DC andAC superimposed processes are possible, but in particular also theoperation with pulsed or modulated feed. The source is in particularsuitable for sputtering metals and/or their alloys in DC, or DC-pulsedoperation. Due to the high target utilization and the good degree ofmaterial utilization, high service lives of the target are achievable,which makes the source well applicable for installations in which highcycle rates are to be achieved and thus high throughputs at higheconomy.

[0047] Aluminum and aluminum alloys are especially often applied,preferably for optical storage such as for example CDs and DVDs(L1-layer DVD9). The previously listed advantages also have the resultthat precious metals can be deposited especially economically. Hereinsilver and its alloys are of special significance since silver withconventional sources yields rather poor degrees of utilization. Inparticular with optical storage plate applications such as CD-R and DVD,silver and silver alloys are of great importance and the sourceaccording to the invention represent hereto an especially economicsolution. The source according to the invention is especially suitablefor disk-form storage plates as well as also magnetic storage plates butin particular for optical storage such as for example for CDs, CDRs,CD-RWs and far preferred for DVDs.

[0048] The sputter source according to the invention permits combiningvery good layer thickness distribution with simultaneously high transferrate and target utilization degree, long target service life and highspecific deposition rate. Thereby that the target has great thickness atthose sites at which the essential sputter zones are located, hightarget utilization of more than 40%, even more than 45%, becomespossible, wherein through the special shaping of the configuration withrespect to the substrate a transfer factor of better than 45%, evenbetter than 50%, is possible. With round target configurationsespecially in the outer region of the target a large material proportionis present, which also ensures through the sputter zone applied in theouter regions a high material utilization. The combination of a concavetarget development at low target substrate distance and small targetdiameters with the feasibility of eroding large target thicknessesuniformly and yet to be able to attain over the entire service life agood and stable distribution, makes possible the production inparticular of storage plates in an especially economic manner. A furtheradvantage of the source configuration according to the inventioncomprises that only a portion of the magnet system can be rotatedleading to simpler manner of construction and, through the small outercircumference of the rotating magnet system part, denotes a significantadvantage for the simple construction of the cathode.

1. Magnetron sputter source with a round target body (1), whose frontside has a sputter face (20, 21), with a magnet system (2, 3, 4, 5, 10,11) comprising an inner pole (4) and an outer pole (3) annularlyencompassing the former, such that a magnetic field (B) develops overthe sputter face (20, 21) in the form of a closed tunnel-like loop aboutthe central source axis (6), and that at least a portion of the magnetsystem (2, 3, 4, 5, 10, 11) is supported rotatable about the source axis(6) and it is operationally connected with driving means (30),characterized in that the annular outer pole (3) is not disposed in thesame plane with the inner pole (4) and in the margin region of the roundtarget body (1) is elevated and the rotatable magnet system partreceives the inner pole (4) disposed eccentrically to the axis (6) andreceives a second outer pole part (11) disposed between outer pole (3)and inner pole (4), such that with rotation the tunnel loop of themagnetic field (B) sweeps eccentrically over the sputter face (20, 21).2. Source as claimed in claim 1, characterized in that the magnet system(2, 3, 4, 5, 10, 11) comprises permanent magnets, in particular of thetype rare-earths magnets such as comprising cobalt-samarium and/orneodymium.
 3. Source as claimed in claim 2, characterized in that themagnet system (2, 3, 4, 5, 10, 11) comprises a magnetic yoke (5, 10) ofhighly permeable material for the return of the magnetic circuit withinthe source configuration.
 4. Source as claimed in claim 3, characterizedin that the yoke (5, 10) is developed concentrically in two parts andcomprises a first outer stationary part (5) and a second inner rotatablysupported part (10).
 5. Source as claimed in claim 4, characterized inthat the inner yoke part (10) receives the inner pole (4) and outer polepart (11).
 6. Source as claimed in one of claims 1 to 5, characterizedin that at least one of the poles (3, 4, 11), preferably all three poles(3, 4, 11), comprises permanent-magnetic material.
 7. Source as claimedin one of the preceding claims 1 to 6, characterized in that themagnetic circuit of the magnet system is developed such that thedirectional characteristic with respect to the sputtered-off particlesof the sputter face (20, 21) onto a flat substrate (s) disposed in frontis substantially maintained constant during the sputter operation overthe service life of the target body (1).
 8. Source as claimed in one ofthe preceding claims 1 to 7, characterized in that the sputter face (20)is at least in subregions developed concavely.
 9. Source as claimed inone of the preceding claims 1 to 8, characterized in that in the sourcecenter along the source axis (6) a center mask (16) is provided, whichpenetrates the target body in the direction to the substrate plane (s)and the latter is not electrically connected to the target andpreferably forms a counter electrode to the target (1), in particular ananode, or is disposed such that it is floating.
 10. Source as claimed inone of the preceding claims 1 to 9, characterized in that the targetbody (1) encompasses annularly the center axis (6), in particular thecenter mask (16), and the sputter face (20) is preferably developedconcavely or channel-form, and preferably has in cross sectionsubstantially a V-form sputter original face (20).
 11. Source as claimedin one of the preceding claims 1 to 10, characterized in that the outerpole magnet (3) is disposed in the region of the periphery of the targetbody (1) and the sputter face (20).
 12. Source as claimed in one of thepreceding claims 1 to 11, characterized in that a counter electrode (15)encompasses the target body (1) in the region of the sputter faceperiphery (20), wherein such forms a receiving opening (28) forreceiving a substrate (s).
 13. Source as claimed in claim 12,characterized in that the greatest distance (d) between the targetoriginal face (20) and the planes of the receiving opening (28) is inthe range from 20 to 60 mm, preferably between 20 to 40 mm.
 14. Sourceas claimed in claim 13, characterized in that the receiving opening (28)can receive substrates (s) with a diameter of 50 to 150 mm, preferablyof 70 to 150 mm.
 15. Source as claimed in one of claims 13 to 14,characterized in that the diameter of the sputter face (20) is greaterthan the diameter of the receiving opening (28), preferably by up to30%, in particular by up to 25%.
 16. Source as claimed in one of claims1 to 15, characterized in that the target body (1) comprises metal or ametal alloy, preferably comprises one of the metals silver, gold oraluminum.
 17. Use of the sputter source as claimed in one of claims 1 to16 for the sputter coating of storage plates, in particular for opticalstorage such as CDs, CDRs, CD-RWs and preferably for DVDs.